Avoid r8153_ecm is compiled as built-in, if r8152 driver is compiled
as modules. Otherwise, the r8153_ecm would be used, even though the
device is supported by r8152 driver.

Fixes: c1aedf01 ("net/usb/r8153_ecm: support ECM mode for RTL8153")
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Hayes Wang <hayeswang@realtek.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/1394712342-15778-394-Taiwan-albertk@realtek.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>